import math

x1,y1,x2,y2 = tuple(float(n) for n in input().split())
D = math.sqrt((x2-x1)**2 + (y2-y1)**2)
print("{:.8f}".format(D)) import math math x1,y1,x2,y2 = tuple(float(n) for n in input().split()) x1 tuple(float(n) for n in input().split()) tuple float(n) float n y1 x2 y2 D = math.sqrt((x2-x1)**2 + (y2-y1)**2) D math.sqrt((x2-x1)**2 + (y2-y1)**2) math.sqrt math sqrt (x2-x1)**2 + (y2-y1)**2 (x2-x1)**2 x2-x1 x2 x1 2 (y2-y1)**2 y2-y1 y2 y1 2 print("{:.8f}".format(D)) print "{:.8f}".format(D) "{:.8f}".format "{:.8f}" format D y2 = tuple(float(n) for n in input().split()) tuple(float(n) for n in input().split()) y2 x2,y2 = tuple(float(n) for n in input().split()) tuple(float(n) for n in input().split()) x2 y1,x2,y2 = tuple(float(n) for n in input().split()) tuple(float(n) for n in input().split()) y1 x1,y1,x2,y2 = tuple(float(n) for n in input().split()) tuple(float(n) for n in input().split()) x1 D = math.sqrt((x2-x1)**2 + (y2-y1)**2) math.sqrt((x2-x1)**2 + (y2-y1)**2) D
import math

x1,y1,x2,y2 = tuple(float(n) for n in input().split())
D = math.sqrt((x2-x1)**2 + (y2-y1)**2)
print("{:.8f}".format(D))
